I wish I had loads of cash. My empires are seldom flowing with cash for long. Maybe my army is too big. But 60,000 upkeep a turn is a fair price to play for secure borders on every front. You could just keep churning out Praetorians or Silvershields or whatever your most expensive unit is to keep profits lowered, whilst simulatenously building up a strong military. Or fill your building queues with buildings, even if you aren't planning to build them. IIRC, money goes from your treasury whenever you put something into the queue even if it won't be built for another 10 years or more. This means your money is tied up in construction and won't contribute to your governor's bad traits. When you need the money back, remove the buildings from the build queues. That's the theory anyway.

It doesn't matter a great deal if you're making silly amounts of money and your governors get bad traits because you obviously weren't using all that money anyway, so a bit of wastage isn't disasterous.

The bad traits tend to start at 50K, then increase at 100K, and again at 150K if I remember correctly.

You can mod the character traits file to change the probabilities of picking up bad traits but I personally wouldn't change it that much. You need some disecomonies of scale to help keep your empire from getting endlessly powerful. That said, once you're massive and your empire is a money making machine, nothing can stop you anyway.